Four-dimensional processing of deformable cardiac PET data

A 4D deformable motion algorithm is described for use in the motion compensation of gated cardiac PET. The algorithm makes use of temporal continuity and a non-uniform elastic material model to provide improved estimates of heart motion between time frames. Temporal continuity is enforced by two methods. First, a prediction motion field is calculated using an assumption of constant particle velocity between time frames. Second, incremental motion fields are used as initializations for the estimation of motion fields between distant time frames. The prediction fields augment the algorithm´s ability to estimate motion between noisy adjacent time frames, and the concatenated incremental motion fields improve estimation for large deformations. The estimated motion fields are used to establish a voxel correspondence between volumes, and produce a motion compensated composite volume